JP2008194670A - Gas treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain stable gas treatment capacity and high gas treatment capacity and to achieve cost reduction. <P>SOLUTION: Honeycomb structures 4 are arranged with intervals along the passing direction (the direction from the inlet of a duct 1 to the outlet thereof) of a gas GS to be treated. The honeycomb structures 4-1 and 4-2 are set as a first honeycomb structure group and an electrode 8 is arranged outside the honeycomb structure 4-1 as a first electrode while an electrode 9 is arranged outside the honeycomb structure 4-2 as a second electrode. The honeycomb structures 4-3 and 4-4 are set as a second honeycomb structure group and the electrode 9 is arranged outside the honeycomb structure 4-3 as a first electrode while an electrode 10 is arranged outside the honeycomb structure 4-4 as a second electrode. High voltages having different values are applied across the electrodes 8 and 9 and across the electrodes 9 and 10 to produce plasma in the through-holes (cells) 4a of the honeycomb structures 4 and the space gaps 12 between the honeycomb structures 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas processing apparatus that purifies harmful gas contained in a gas to be processed.

  2. Description of the Related Art Conventionally, a technique for purifying harmful gas contained in exhaust gas by creating a plasma state by performing high voltage discharge in the exhaust gas is known. In recent years, this technology is being applied to a purification device for purifying factory exhaust and an air purifier for purifying indoor air for the purpose of deodorization.

  Plasma that is in a thermally non-equilibrium state, that is, in which the electron temperature is much higher than the temperature of the gas or ion (non-equilibrium plasma (hereinafter simply referred to as plasma)) is the ion or radical produced by electron collision. Promotes a chemical reaction that does not occur at room temperature, and is considered useful in hazardous gas treatment as a medium that can efficiently remove or decompose harmful gases. The key to practical use is to improve the energy efficiency during processing and to convert it into a completely safe product after processing with plasma.

In general, plasma at atmospheric pressure is generated by gas discharge or electron beam. There are nitrogen oxides (NOx), sulfur oxides (SOx), chlorofluorocarbons, CO ₂ , volatile organic solvents (VOC), etc. that are currently being considered for application. Above all, NOx is contained in the exhaust gas of a car, so that it needs to be put into practical use immediately.

The phenomenon in discharge plasma (plasma generated by gas discharge) in NOx removal is that ions and radicals generated primarily by electron collision cause an initial reaction, and N ₂ , H ₂ O, It is thought that it is converted into each particle such as NH ₄ NO ₃ .

Further, when the harmful gas is, for example, acetaldehyde or formaldehyde, the harmful gas is converted into CO ₂ and H ₂ O by passing plasma. In this case, ozone (O ₃ ) is generated as a by-product.

  FIG. 5 illustrates a main part of a conventional gas processing apparatus using discharge plasma (see, for example, Patent Document 1). In the figure, reference numeral 1 denotes a duct (ventilation path) through which a processing target gas (air containing toxic gas) GS flows. Inside the duct 1, a discharge electrode 2 and a ground electrode 3 are arranged along the passing direction of the processing target gas GS. Are arranged alternately, and a honeycomb structure 4 having a large number of through holes 4 a called cells is disposed between the electrodes 2 and 3. Reference numeral 5 denotes a high voltage power source. The honeycomb structure 4 is formed of an insulator such as ceramics, and Patent Document 2 also has an example of its use.

  The discharge electrode 2 is formed of a metal mesh, a fine wire, a needle-like body, or the like. Each discharge electrode 2 is connected to the + pole of the high voltage power supply 5 by a conducting wire 6. The ground electrode 3 is formed of a metallic mesh or the like. Each ground electrode 3 is connected to the negative pole of the high voltage power supply 5 by a conducting wire 7.

  In this gas processing apparatus, the gas GS to be processed is caused to flow through the duct 1, and a high voltage (several kV to several tens kV) from the high voltage power supply 5 is applied between the discharge electrode 2 and the ground electrode 3. Thereby, plasma is generated in the through-holes 4a of the honeycomb structures 4, and harmful gases contained in the processing target gas GS are decomposed into harmless substances by ions and radicals generated in the plasma.

JP 2000-140562 A JP 2001-276561 A

  However, the conventional gas processing apparatus described above has the following problems (1) to (3).

  (1) Although a large number of honeycomb structures 4 are provided, a technique for generating uniform plasma without variations has not been established, and variations in the performance of the honeycomb structures 4 occur. For example, impedance values may be different even in the same honeycomb structure 4, and impedance values may be different in one honeycomb structure 4, for example, at the top and bottom thereof, so that uniform plasma can be generated as a whole. Therefore, the gas processing capacity becomes unstable. Further, since plasma is generated only through the through holes 4a, the amount of plasma generated is small and the gas processing capacity is low.

  (2) The honeycomb structure 4 has a characteristic of low impedance when moisture is absorbed and high impedance when dried. When the honeycomb structure 4 becomes low impedance, the flowing current increases and the discharge electrode 2 and the ground electrode 3 When the high voltage value applied between them decreases and the honeycomb structure 4 becomes high impedance, the flowing current decreases and the high voltage value applied between the discharge electrode 2 and the ground electrode 3 increases. The high voltage power supply 5 that can obtain a high voltage value that can secure a desired plasma generation amount with respect to such a change in the high voltage value is very expensive including the man-hours required for its design.

(3) Since the discharge electrode 2 and the ground electrode 3 are provided for each of the honeycomb structures 4, the number of parts is large, the structure is complicated, and the cost is increased.
(4) Since a high voltage is generated by a single power source, further improvement in plasma generation cannot be expected, and improvement in gas processing capacity will reach its peak.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a gas processing apparatus having a stable gas processing capability and a high gas processing capability at a low cost.

  In order to achieve such an object, the present invention provides a plurality of honeycomb structures having a large number of through holes arranged at intervals in the ventilation passage and through which the gas to be processed passes, and adjacent to each other among the plurality of honeycomb structures. A plurality of matching honeycomb structures are used as a group of honeycomb structures, and each honeycomb structure group includes first and second electrodes disposed outside the honeycomb structures positioned at both ends thereof, and each honeycomb structure. A high voltage source is provided between the first electrode and the second electrode of the group to generate a plasma in the through holes of the honeycomb structure and the space between the honeycomb structures by individually applying a high voltage. .

  According to the present invention, a plurality of honeycomb structures are arranged in the ventilation path at intervals, and a plurality of adjacent honeycomb structures among the plurality of honeycomb structures are used as a group of honeycomb structures, and these honeycomb structures are arranged. The first and second electrodes are arranged outside the honeycomb structure located at both ends of each structure group.

  For example, when a plurality of honeycomb structures are divided into a first honeycomb structure group and a second honeycomb structure group, the first honeycomb structure group is positioned outside the honeycomb structure group located at both ends of the first honeycomb structure group. One electrode and a second electrode are arranged, and the first electrode and the second electrode are arranged outside the honeycomb structure group located at both ends of the second honeycomb structure group. In this case, there are a first electrode and a second electrode arranged for the first honeycomb structure group, and a first electrode and a second electrode arranged for the second honeycomb structure group. However, the second electrode disposed with respect to the first honeycomb structure group and the first electrode disposed with respect to the second honeycomb structure group may be used as a common electrode.

  A high voltage is individually applied between the first electrode and the second electrode of each honeycomb structure group. By applying this high voltage, plasma is generated in the through holes of the honeycomb structure and the space between the honeycomb structures, and harmful gas contained in the gas to be processed is decomposed into harmless substances when passing through the plasma.

  In the present invention, plasma is generated not only in the through holes of the honeycomb structure but also in the space (air layer) between the honeycomb structures. For this reason, in addition to the molecular decomposition effect of harmful gas in the through holes, the molecular decomposition effect of harmful gas in the space between the honeycomb structures is added. The synergistic effect with the molecular decomposition effect in space promotes the decomposition of harmful gases into harmless substances. A large amount of uniform plasma is generated in the space between the honeycomb structures.

Further, in this invention, since an air layer is provided between the honeycomb structures, the impedance between the electrodes is stabilized, and the change in the flowing current with respect to the impedance change due to moisture absorption / drying of the honeycomb structure is reduced. Eliminates the need to use specially designed high voltage power supplies.
In the present invention, the electrodes need only be provided for each honeycomb structure group, and it is not necessary to arrange the electrodes for each honeycomb structure, the number of parts is reduced, the structure is simplified, and the number of assembly steps is reduced.

  Further, in the present invention, since a high voltage is individually applied between the first electrode and the second electrode of each honeycomb structure group, the potential in the space between the honeycomb structures is stably increased to a high electric field state. Therefore, plasma can be generated stably, and the gas processing capacity can be improved as compared with the case of using a single power source.

  In the present invention, a high voltage is individually applied between the first electrode and the second electrode of each honeycomb structure group. However, a high voltage having a different voltage value may be applied, or a high voltage of a different voltage type may be applied. It may be applied as a voltage, or may be applied as a high voltage having a different frequency. By varying the voltage type or the frequency, the potential of the space between the honeycomb structures can be changed to a complex high electric field state, and plasma can be stably generated.

  According to the present invention, a plurality of honeycomb structures are arranged at intervals in the ventilation path, and a plurality of adjacent honeycomb structures among the plurality of honeycomb structures are made into one group of honeycomb structures, and the honeycombs First and second electrodes are arranged outside the honeycomb structure located at both ends of each structure group, and a high voltage is individually applied between the first electrode and the second electrode of each honeycomb structure group. As a result, the plasma is generated not only in the through holes of the honeycomb structure but also in the spaces between the honeycomb structures. In addition to the molecular decomposition effect of harmful gases in the through holes, the honeycomb structure In addition to the molecular decomposition effect of harmful gas in the space between, and the synergistic effect of the molecular decomposition effect in the through hole and the molecular decomposition effect in the space between the honeycomb structures, the harmful gas is converted into a harmless substance. Decomposition is promoted, Scan processing capacity is increased. Further, since a large amount of uniform plasma is generated in the space between the honeycomb structures, the gas processing capacity is stabilized.

Further, according to the present invention, since the air layer is provided between the honeycomb structures, the impedance between the electrodes is stabilized, and the change in the flowing current is reduced with respect to the impedance change due to moisture absorption / drying of the honeycomb structure. Therefore, it is not necessary to use a special high-voltage power supply designed in the above-mentioned manner, and a commercially available inexpensive high-voltage power supply can be used.
In addition, according to the present invention, the electrodes need only be provided for each honeycomb structure group, and it is not necessary to arrange the electrodes for each honeycomb structure. As a result, the number of parts is reduced, the structure is simplified, the number of assembled parts can be reduced, and the cost can be reduced.

  Further, according to the present invention, since the high voltage is individually applied between the first electrode and the second electrode of each honeycomb structure group, the high voltage having different voltage values is applied. The voltage in the space between the honeycomb structures is stably maintained in a high electric field state by applying a high voltage with a different voltage type or applying a high voltage with a different frequency. Can be generated stably, and the gas processing capacity can be improved as compared with the case of using a single power source.

Hereinafter, the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
FIG. 1 is a diagram showing a main part of an embodiment (Embodiment 1) of a gas processing apparatus according to the present invention. 5, the same reference numerals as those in FIG. 5 denote the same or equivalent components as those described with reference to FIG. 5, and the description thereof will be omitted.

  In this embodiment, a plurality of honeycomb structures 4 are arranged in the duct 1 along the passing direction of the processing target gas GS (the direction from the inlet to the outlet of the duct 1) at intervals. In this example, a gap G1 is provided between the honeycomb structures 4-1 and 4-2, and a gap G2 is provided between the honeycomb structures 4-3 and 4-4. ˜4-4 are arranged in the duct 1.

  In addition, adjacent honeycomb structures 4-1 and 4-2 among the plurality of honeycomb structures 4 in the duct 1 serve as a first honeycomb structure group, and honeycombs positioned at both ends of the first honeycomb structure group. Outside the structures 4-1 and 4-2, an electrode 8 is arranged as a first electrode, and an electrode 9 is arranged as a second electrode.

  Similarly, adjacent honeycomb structures 4-3 and 4-4 among the plurality of honeycomb structures 4 in the duct 1 are set as the second honeycomb structure group, and are positioned at both ends of the second honeycomb structure group. Outside the honeycomb structures 4-3 and 4-3, the electrode 9 is arranged as the first electrode, and the electrode 10 is arranged as the second electrode.

  In the present embodiment, the electrode 9 is a common electrode that serves as both the second electrode of the first honeycomb structure group and the first electrode of the second honeycomb structure group. The second electrode of the honeycomb structure group and the first electrode of the second honeycomb structure group may be independent electrodes.

  The electrodes 8, 9 and 10 are made of metal mesh so that the gas to be processed GS passes through. In the present embodiment, the high voltage power source (high voltage source) 5 includes a first high voltage power source 5-1 and a second high voltage power source 5-2 having different voltage values, and the electrode 8 has The lead wire 11 is connected to the + pole of the high voltage power source 5-1 by the conductive wire 11, the electrode 9 is connected to the negative pole of the high voltage power source 5-1 and the positive pole of the high voltage power source 5-2 by the lead wire 12, and the electrode 10 is connected to the lead wire 13. Is connected to the negative pole of the high voltage power source 5-2.

  The honeycomb structure 4 is formed of an insulator such as ceramics, and has a large number of through holes (cells) 4a through which the processing target gas GS passes. The number of through holes 4a per unit area of each honeycomb structure 4 is made equal. That is, in this embodiment, the same type of honeycomb structures 4-1 to 4-4 having the same number of through holes 4a per unit area are used.

  In this embodiment, the gap G1 between the honeycomb structures 4-1 and 4-2 is equal to the gap G2 between the honeycomb structures 4-3 and 4-4, for example, 0.5 mm. It is set to several mm. As a result, an air layer 14-1 is formed between the honeycomb structures 4-1 and 4-2, and an air layer 14-2 is formed between the honeycomb structures 4-3 and 4-4. . Hereinafter, the air layer 14 (14-1, 14-2) is referred to as a space gap.

  In this gas processing apparatus, the gas GS to be processed is caused to flow into the duct 1, a high voltage from the high voltage power source 5-1 is provided between the electrodes 8 and 9, and a high voltage power source 5 is provided between the electrodes 9 and 10. High voltage from 2 is applied. As a result, plasma is generated in the through holes 4a of the honeycomb structure 4 and the space gap 14 between the honeycomb structures 4, and harmful gases contained in the processing target gas GS are harmless by ions and radicals generated in the plasma. It is decomposed into new substances.

  In the present embodiment, plasma is generated not only in the through holes 4 a of the honeycomb structure 4 but also in the space gap 14 between the honeycomb structures 4. For this reason, in addition to the molecular decomposition effect of the harmful gas in the through hole 4a, the molecular decomposition effect of the harmful gas in the space gap 14 between the honeycomb structures 4 is added, and the molecular decomposition effect in the through hole 4a is further increased. The synergistic effect with the molecular decomposition effect in the space gap 14 between the honeycomb structures 4 promotes the decomposition of harmful gases into innocuous substances and increases the gas processing capacity. Further, in the space gap 14 between the honeycomb structures 4, an electric field spreads from the edge surface of the opposing through hole 4a, and a large amount of uniform plasma is generated. Thereby, the influence by the dispersion | variation in the plasma which generate | occur | produces in the through-hole 4a becomes small, and gas processing capability is stabilized.

  In this embodiment, since the space gap 14 which is an air layer is provided between the honeycomb structures 4, the impedance between the electrodes is stabilized by the space gap 14, and the impedance change due to moisture absorption and drying of the honeycomb structure. The change in the current that flows is reduced. As a result, the change in the high voltage value applied between the electrodes is reduced, and a commercially available inexpensive high voltage power supply can be used as the high voltage power supply 5 instead of a special high voltage power supply designed exclusively. It becomes like this.

  Further, in this embodiment, the electrodes need only be provided for each honeycomb structure group, and it is not necessary to arrange the electrodes for each honeycomb structure 4. As a result, the number of parts is reduced, the structure is simplified, the number of assembly steps is reduced, and the cost can be reduced.

  In this embodiment, a high voltage from the first high-voltage power source 5-1 is applied between the first electrode 8 and the second electrode 9 of the first honeycomb structure group to the second honeycomb structure. Since the high voltage from the second high voltage power source 5-2 is individually applied between the first electrode 9 and the second electrode 10 of the structure group, the space gaps 14-1 and 14-2 are applied. Thus, it is possible to stably maintain a high electric field state and generate plasma stably, and it is possible to improve the gas processing capacity as compared with the case of using a single power source as in the prior art. Further, by setting the high voltage from the high voltage power supply 5-1 and the high voltage from the high voltage power supply 5-2 to different values, the plasma of the first honeycomb structure group and the second honeycomb structure group is changed. It is possible to change the amount of generated harmful gas by changing the generation amount.

[Embodiment 2]
In the first embodiment, the high voltage power supply 5 is a combination of DC high voltage power supplies 5-1 and 5-2 (DC + DC), but a combination of AC high voltage power supplies (AC + AC), Various combinations of voltage types such as a combination of AC high voltage power supply (DC + AC) and a combination of pulse power supply and AC power supply (pulse + AC) are conceivable. Further, when an AC high voltage power supply is used, the frequency may be varied. Further, the number of honeycomb structure groups may be increased to further increase the types of high-voltage power supplies to be individually applied, or to vary the frequency. By changing the voltage type or the frequency, the potential of the space between the honeycomb structures 4 can be changed to a complex high electric field state, and plasma can be generated stably.

  FIG. 2 shows an example in which the high voltage power supply 5 is a combination of AC high voltage power supplies. In this example, an AC high voltage power supply 5-3 is used as the first high voltage power supply, and an AC high voltage power supply 5-4 is used as the second high voltage power supply. In this example, when the frequencies of the high voltage power supplies 5-3 and 5-4 are changed, the space gap 14 (14-1, 14-2) is changed into a complex high electric field state, and plasma is generated in the space gap 14 as a whole. It is possible to reduce the idle period, and to stably generate plasma.

[Embodiment 3]
In the first embodiment, the plurality of honeycomb structures 4 are provided in the duct 1 along the passing direction of the processing target gas GS. However, as shown in FIGS. 3 and 4, the passing direction of the processing target gas GS is performed. A plurality of honeycomb structures 4 may be provided in the duct 1 along a direction orthogonal to the duct 1.

  In this case, since the honeycomb structures 4 are arranged at intervals along the direction orthogonal to the passing direction of the processing target gas GS, the honeycomb structures 4 are arranged along the passing direction of the processing target gas GS. In addition, the time during which the processing target gas GS is exposed to plasma in the through holes 4a of the honeycomb structures 4 and the space gaps 12 between the honeycomb structures 4 becomes longer. As a result, the opportunity for gas decomposition is increased, the gas processing capacity is improved, and it is possible to prevent the gas processing capacity from being lowered in a high-speed flow.

  In the first to third embodiments described above, the number of through holes 4a per unit area of the honeycomb structures 4-1 to 4-4 is equalized. The number of through holes 4a per unit area may be selectively varied. For example, the honeycomb structures 4-1 and 4-2 have a small number of through holes 4a per unit area, and the honeycomb structures 4-3 and 4-4 have a large number of through holes 4a per unit area. Alternatively, the number of through holes 4a per unit area may be increased in the order of honeycomb structures 4-1, 4-2, 4-3, and 4-4.

  When the number of the through holes 4a per unit area is increased in the order of the honeycomb structure 4-1, 4-2, 4-3, 4-4, the honeycomb structure 4-1, 4-2, 4-3, 4 The amount of generated plasma increases in the order of −4, and the types of harmful gases that can be decomposed in each honeycomb structure 4 can be made different.

  For example, in the case where harmful gases A, B, C, and D having higher energy levels in their molecules are included in the processing target gas GS, the harmful gas A included in the processing target gas GS is converted into the honeycomb structure. 4-1 is decomposed, the harmful gas B contained in the processing target gas GS is decomposed by the honeycomb structure 4-2, and the harmful gas C contained in the processing target gas GS is decomposed by the honeycomb structure 4-3. The kind of harmful gas that can be decomposed in each honeycomb structure 4 can be made different, for example, the harmful gas D contained in the target gas GS is decomposed by the honeycomb structure 4-4.

  In this case, when the harmful gas B is decomposed in the honeycomb structure 4-2, the harmful gas A that could not be decomposed by the honeycomb structure 4-1 is decomposed, and the harmful gas C in the honeycomb structure 4-3 is decomposed. At the time of decomposition, harmful gases A and B that could not be decomposed by the honeycomb structures 4-1 and 4-2 are decomposed, and at the time of decomposition of the harmful gas D by the honeycomb structures 4-4, the honeycomb structure 4 Hazardous gases A, B, and C that could not be decomposed by -1,4-2,4-3 are decomposed.

  With such a method, a by-product (for example, ozone) generated during the decomposition of the harmful gas, compared with the case where all the harmful gases A, B, C, and D are decomposed by one honeycomb structure 4. ) Can be reduced.

  In the first to third embodiments described above, the gap G (G1, G2) between the honeycomb structures 4 is made equal, but may be different. When the gaps G1 and G2 between the honeycomb structures 4 are made different, the amount of plasma generated in the space gaps 14-1 and 14-2 is different, and the unit area of the honeycomb structures 4-1 to 4-4 is different. The same operation and effect as when the number of through holes 4a is selectively varied can be obtained. In this case, since the honeycomb structures 4-1 to 4-4 can be the same type of honeycomb structure having the same number of through holes 4a per unit area, the number of parts does not need to be increased.

In the first to third embodiments described above, the honeycomb structure 4 may have a catalyst function of decomposing ozone, and a catalyst for decomposing ozone is provided at a downstream position of the honeycomb structure 4-4. May be.
In Embodiments 1 to 3 described above, the number of honeycomb structures 4 is four. However, as long as two or more honeycomb structure groups can be formed, the number of honeycomb structures 4 is not limited. Good.
Moreover, in Embodiment 1-3 mentioned above, ozone may be generated in large quantities as a by-product, and you may make it divert as an ozone generator.

In addition, this gas processing apparatus can also be applied to so-called reforming for generating a hydrogen-containing gas from hydrocarbons or the like for the purpose of efficiently generating hydrogen used in a fuel cell or the like. For example, in the case of octane (substance relatively close to the average molecular weight of gasoline) C ₈ H ₁₈ , when supplied to this gas treatment device, the chemical reaction represented by the following formula (1) is promoted, and as a result, hydrogen gas is efficiently generated. can do.
C ₈ H ₁₈ + 8H ₂ O + 4 (O ₂ + 4N ₂ ) → 8CO ₂ + 17H ₂ + 16N ₂ ... (1)

It is a figure which shows the principal part of one Embodiment (Embodiment 1) of the gas processing apparatus which concerns on this invention. It is a figure which shows the example (Embodiment 2) made into the combination of alternating current high voltage power supplies as a high voltage power supply. It is a figure which shows the example (in the case of the combination of DC + DC) which provided the some honeycomb structure in the duct along the passage direction of process target gas. It is a figure which shows the example (in the case of the combination of AC + AC) which provided the several honeycomb structure in the duct along the passage direction of process target gas. It is a figure which illustrates the principal part of the conventional gas processing apparatus using discharge plasma.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Duct (ventilation path), 4 (4-1 to 4-4) ... Honeycomb structure, 4a ... Through-hole (cell), 5 (5-1 to 5-4) ... High voltage power supply 8, 9, DESCRIPTION OF SYMBOLS 10 ... Electrode, 14 (14-1, 14-2) ... Spatial gap, G (G1, G2) ... space | interval, GS ... Process target gas.

Claims (4)

A plurality of honeycomb structures having a large number of through holes arranged at intervals in the ventilation path and through which the gas to be treated passes;
A plurality of adjacent honeycomb structures among the plurality of honeycomb structures are regarded as a group of honeycomb structures, and the first and second elements arranged outside the honeycomb structures located at both ends of each honeycomb structure group. Two electrodes;
A high voltage source for generating a plasma in a through hole of the honeycomb structure and a space between the honeycomb structures by individually applying a high voltage between the first electrode and the second electrode of each honeycomb structure group A gas treatment device comprising: The gas treatment device according to claim 1, wherein
The gas processing apparatus, wherein the high voltage source applies a high voltage having a different voltage value between the first electrode and the second electrode of each honeycomb structure group. The gas treatment device according to claim 1, wherein
The gas processing apparatus, wherein the high voltage source applies a high voltage having a different voltage type between the first electrode and the second electrode of each honeycomb structure group. The gas treatment device according to claim 1, wherein
The gas processing apparatus, wherein the high voltage source applies a high voltage having a different frequency between the first electrode and the second electrode of each honeycomb structure group.

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